Process of removing corrosive agents from hydrocarbon oils



Dc. 22, 1931. R. K. s'rRATFoRD ET Al. 1.338031 PROCESS 0.@ REMOVING CORROSIVE AGENTS FROM HYDRIOCAR-BON OILSv Filed Dc. 13. 1927 um os .N

REGLA/Aw lf2 ,SrRA Tpojzp gvwwtou" GORDON W. MC'NTRE HERBERT l!- Mo OR @Mama/W Patented Dec. 22, 1931 REGINALD K. STRATFORD, GORDON ONTARIO, CANADA, ASSIGNORS CORPORATION OF DELAWARE MCINTYRE, AND HERBERT H; MOOR, OF SARNIA, TO STANDARD OIL DEVELOPMENT COMPANY, A

PROCESS 0F REMOVING CORROSIVE AGENTS FROM HIYDROCARIBON OILS Application mea December 1s, y1927. serial No. 239,656.

This invention relates to improvements in removing foreivn substances, especially corrosive agents, from petroleum oils and the like. In a preferred method of carrying out the invention, a continuous stream of crude oil to be purified is heated with an alkaline solution under pressure, the alkaline solution is settled out, and the purified crude oil is piped without further treating to a crude still.

An important object is to provide a continuous method for rendering petroleum oil non-corrosive before it undergoes distillation. In this way, deterioration of equipment is substantially prevented and at the same time the crude oil is putin condition to yield directly a gasoline of excellent quality.

The invention will be fully understood from the following description of one method of operation, read in connection with the accompanying drawing, which is a diagrammatic vertical section of an apparatus suitable for carrying out the method.

In the drawing, numeral 1 denotes a mixing column which may be of the type shown in the U. S. patent to Charles Leaver, No. 1,635,718, granted July 12, 1927. Crude oil containing impurities (for example elementary sulfur, hydrogen sulfide, magnesium chloride, and/or iron chloride) is supplied by pump 2 and pipe 3 to the column 1. An alkaline solution, preferably a 34 B. water solution of sodium hydroxide, is conveyed through pipe 4 by pump 5. Pipes 3 and 4 connect with a pipe 6 which opens into column 1. This column is heated in any suitable way, as by means of steam circulated through inlet and withdrawal pipes 7 and 8. The oil is preferably preheated before entering the mixing column. Heat from oil vapors evolved in the system or any other suitable source of heat may be used for this purpose.

The mixed oil and solution leave column 1 through pipe 9. Pressure control valves 6a and 9d are installed in pipes 6 and 9 respectively. The temperature of the outflowing mixture may be about 220 to 240 F. The inlet pressure is desirably about 40 to 50 lbs. per square inch and the outlet pressure about 20 to 30 lbs.

The mixture is discharged through pipe 9 into a settling tank 10. One or more other settling tanks 11 may be connected in series with tank 10 by a pipe or pipes 12. The alkaline solution is withdrawn through valved pipes 13 and 14 from the 4lower part of the settling tanks and is recirculated, so long as it retains its effectiveness, through pipe 4 and themixing' column 1. When necessary, the spenty solution containing the I impurities removed from the oil may be withdrawn through a branch outlet pipe 13 and fresh solution supplied from tank 15, with which pipe 5f-connects. After settling, the oil is drawn ofi from th last settling tank through pipe 16 directly to the tower 17 of a crude still 18. It is preferred to maintain a superatmospheric pressure of about 10 tov 20lbs. on the oil in the settling tanks and for this purpose a pressure control Valve 16a is, installed in pipe 16. The still 18 may be run with a liquid temperature of about 4700 to 510o F. and a temperature of about 280 to 300O F. at the top` r1`he amount and concentration of alkaline i solution required will vary with the impurities in the crude oil or distillate to be treated. Enough of the solution is supplied in all cases to remove or destroy an substances corrosive in themselves or capa le of yield- .ing-corrosive products during the handling of the oil. We generally prefer to pass about equal volumes of oil and solution together through the mixing column. The solution separates readily from the oil in the settling tanks and the oil is still hot when it enters the tower.

The invention is not limited to the temperatures, pressures, and other precise conditions above referred to, but these are merely given for illustration. As a general indication of the range otpermissible temperatures and pressures, it may be said that in treating crude oils such as those from the midcontinent fields, temperatures between 180 F. and 260O F. and pressures between 20 lbs.

per square inch Vand '100 lbs. `per square inch are desirable. Vhile Vthe treatment .described is sufficient in most cases, Athe use of doctor solution or other purifying agent may sometimes be required, particularly when the oil contains a large percentage of the higher mercaptans. Such auxiliary treat may be applied either before or after distillation.

Treating with .hot caustic under pressure as describedmay be applied to reduced crudes, andthe like, as Well as directly'to crude oils. A reduced crude -or lubricating distillate, f or example, may ,be passed Vcontinuously while still hot Afrom the still to the treating and settling equipment, yand thence to `redistil'lation.

Various changes and alternative lprocedures may be made Within the scope of the appended claims, in which we desire .to claim all novelty inherent in the invention as lbroadly as the prior art permits.

We claim:

1. The method of treating crude Vpetroleum Dil to remove chlorides, elementary .sulfur and hydrogen sulfide, which `comprises heating a continuous stream of mixed crude oil and alkaline solution under greater Ythan atmospheric pressure maintaining the temperatures below the cracking temperatures of the oil, reducing the pressure, continuously passing 3he heated mixture under reduced but greater :han atmospheric pressure through enlarged zones whereby impurities are ysettled from :he crude oil, and distilling the purified oil.

2. The method of treating crude petroleum )il to remove chlorides, elementary sulfur ind hydrogen sulfide, which comprises heatlng a continuous stream of mixed crude oil ind alkaline solution under a pressure of apvoroximately 40-50 lbs. per square inch and L temperature of approximately 180-260 F., educing the pressure, continuously passing ',he heated mixture under a pressure of aporoximately 20-30 lbs. per square inch ;hrough enlarged zones whereby impurities tre settled from the crude oil, and distilling ;he purified oil.

REGINALD K. STRATF ORD. GORDON MCINTYRE. HERBERT H. MOOR. 

